Increasing the light output of any given lamp is a constant effort. Beyond gaining small advantages by tweaking the filament or the environment in which the filament operates it is generally necessary supply more power, that is, increase the wattage. While the latter technique works, it also increases the cost of operation. Therefore, it is desirable to increase the light out put of lamps without increasing the wattage. U.S. Pat. No. 3,983,513, issued Sep. 28, 1976, suggests that this can be accomplished by providing a reflective coating on the inside of a portion of large spherical or hemispherical lamp envelopes; however, providing internal coatings on lamp envelopes is a difficult and costly endeavor. Also, such a technique does not readily adapt to cylindrical lamp envelopes.